Grateloupia turuturu, commonly called the devil's tongue weed, is a marine species of Rhodophyta (red algae), a type of seaweed, native to East Asia (China, Japan, Korea) and parts of eastern Russia.

In Europe, it is found in France, Italy, the Netherlands, Portugal, Russia, Spain, the United Kingdom, and the Channel Islands.

Several small invertebrates live in proximity to G. turuturu populations, including shrimps, snails, adolescent fish and crabs.

[7] Germination of this species is similar to that of many other naturally occurring seaweed, where large dense masses of non-motile aplanospores are released into the environment; since discharging spores of red algae cannot swim they must rely on water currents to transport them.

[12] Originating from the northwest Pacific, Grateloupia turuturu has become dispersed profoundly being recorded in regions of Australia, New Zealand, Northeastern United States, Western Europe and the Mediterranean.

The results of the experiment suggested that G. turuturu waited for disturbances in the environment that reduced the abundance of competitors, before increasing in population for a particular habitat.

This impact can be seen by observing native biota such as the five major plant species in the North Atlantic (Chondrus crispus, Mastocarpus stellatus, Palmaria palmata, Saccharina latissima, and S. longicruris) which all occur within low shallow subtidal zones—the same environment in which G. turuturu thrives.

Due in part to its size, it is able to block the amount of sunlight its understory vegetation receives,[10] this is why enhanced growth of Grateloupia could cause a shift or reduced diversity of neighboring organisms such as, other native seaweeds, marine life, and bacteria.

Based on this experiment, extended drying periods and heat treatment could serve as environmentally friendly countermeasures to G. turuturu invasion.